I was wondering if there was a way to add a range of IPs to the "Debugging IP Addresses" page in the CF Administrator. I would like to use this feature to keep most unwanted people from seeing the messages, but everyone who needs access is using dynamic IP addresses or is using a VPN so I can't have a set list of a few IPs. For example, could I add something like 123.123.*.* ?

No, I don't think it will let you use anything except actual IP addresses. You could accomplish what you want in code pretty easily, though, by enabling debug output universally then disable it using the CFSETTING tag and a bit of conditional logic.

That said, you should not of course have debugging enabled in production as it will significantly degrade performance - whether users see the debug output or not.